Callpage - Turn website visitors into sales calls. Use CallPage and provide immediate free phone callback to your leads in 28 seconds.
Hunter - Find all the email addresses related to a domain
Upcall - Upcall enables you to crowdsource your outbound calls. Collaborate with 1000+ on-demand callers worldwide for sales, marketing and customer support calls. Free trial.
Snov.io - More leads. More sales. More revenue.
HeyHi.sg - Video call with interactive whiteboard
MailDump Verifier - Powerful Emails Verifying Tool that helps verify email address or validate email addresses